scholarly journals Challenging the growing rabbit with a moderately pathogenic E. coli under ad libitum or limited feed intake conditions: impact on digestive physiology, bacterial communities, and on post-weaning growth

2021 ◽  
Vol 29 (1) ◽  
pp. 1
Author(s):  
M. Martignon ◽  
C. Burel ◽  
D. Licois ◽  
E. Reperant ◽  
G. Postollec ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bacterial Community ◽  
Feed Intake ◽  
Digestive Physiology ◽  
Lower Growth ◽  
E Coli ◽  
Intake Level ◽  
Lower Growth Rate ◽  
Ad Libitum ◽  
The Impact

The impact of a challenge with moderately pathogenic <em>Escherichia coli</em> O128:C6 on the digestive physiology and gut bacterial community of growing rabbits under two feeding programmes was analysed. Upon weaning (28 d old), 180 rabbits were allocated to four groups (9 cages of 5 rabbits per group) for two weeks: group C100 was non-inoculated and fed <em>ad libitum</em>; C70 was non-inoculated and feed intake was limited to 70% of C100; I100 and I70 were inoculated and fed <em>ad libitum</em> or restricted to 70%, respectively. At the age of 31 d (D0), rabbits were orally inoculated with <em>E. coli</em> (2.2×108 colony forming units/rabbit). The effects of inoculation spiked on D4, with a 28% lower growth rate for I100 than for C100. Limited feed intake reinforced the inoculation’s effects on growth: I70 had a 66% lower growth rate than C70. The morbidity rate peaked at 42% between D4 and D7 for inoculated groups, without significant effect of the feed intake level. <em>E. coli</em> concentration peaked on D5/D6 in the caecum of the I100 and I70 groups. Inoculation reduced by 30% (<em>P</em>&lt;0.05) the villus height/crypt depth and villus/crypt area ratios in the ileum, with no significant effect of the intake level. Inoculation was associated with a tenfold increase in serum haptoglobin (<em>P</em>&lt;0.001) for both <em>ad libitum</em> and restricted rabbits. On D5, the inoculation modified the structure of the ileal bacterial community (<em>P</em>&lt;0.05), but not that of the caecum. The feed intake level did not affect either the structure or diversity of the bacterial community, both in the ileum and caecum.

scholarly journals Titration and Conditional Knockdown of the prfB Gene in Escherichia coli: Effects on Growth and Overproduction of the Recombinant Mammalian Selenoprotein Thioredoxin Reductase

2006 ◽  
Vol 73 (2) ◽  
pp. 432-441 ◽  
Author(s):  
Olle Rengby ◽  
Elias S. J. Arnér
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Essential Gene ◽  
Thioredoxin Reductase ◽  
Lower Growth ◽  
E Coli ◽  
Native Promoter ◽  
Lower Growth Rate ◽  
The Cost ◽  
Translational Termination

ABSTRACT Release factor 2 (RF2), encoded by the prfB gene in Escherichia coli, catalyzes translational termination at UGA and UAA codons. Termination at UGA competes with selenocysteine (Sec) incorporation at Sec-dedicated UGA codons, and RF2 thereby counteracts expression of selenoproteins. prfB is an essential gene in E. coli and can therefore not be removed in order to increase yield of recombinant selenoproteins. We therefore constructed an E. coli strain with the endogenous chromosomal promoter of prfB replaced with the titratable PBAD promoter. Knockdown of prfB expression gave a bacteriostatic effect, while two- to sevenfold overexpression of RF2 resulted in a slightly lowered growth rate in late exponential phase. In a turbidostatic fermentor system the simultaneous impact of prfB knockdown on growth and recombinant selenoprotein expression was subsequently studied, using production of mammalian thioredoxin reductase as model system. This showed that lowering the levels of RF2 correlated directly with increasing Sec incorporation specificity, while also affecting total selenoprotein yield concomitant with a lower growth rate. This study thus demonstrates that expression of prfB can be titrated through targeted exchange of the native promoter with a PBAD-promoter and that knockdown of RF2 can result in almost full efficiency of Sec incorporation at the cost of lower total selenoprotein yield.

scholarly journals FREQUENCY-DEPENDENT SELECTION FOR PLASMID-CONTAINING CELLS OF ESCHERICHIA COLI

Genetics ◽  
1979 ◽  
Vol 91 (4) ◽  
pp. 627-637
Author(s):  
Julian Adams ◽  
Thomas Kinney ◽  
Susan Thompson ◽  
Lori Rubin ◽  
Robert B Helling
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Lower Growth ◽  
Frequency Dependent ◽  
Dependent Effect ◽  
Frequency Dependent Selection ◽  
E Coli ◽  
Lower Growth Rate ◽  
Selection For ◽  
Free Strain

ABSTRACT Colicin-producing plasmid-containing cells of E. coli exhibit frequency dependent selection when grown in glucose-limited continuous culture with the corresponding plasmid-free strain. The bases of this frequency-dependent effect are shown to be (1) the lower growth rate of the plasmid-containing strain under these conditions, and (2) the production of colicin, which attenuates the growth rate of the plasmid-free strain. These results are discussed in relationship to the maintenance of genetic variation in prokaryotes.

509 Late-Breaking: Effect of a Sensory Additive on Sow Reproductive Performance

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 206-206
Author(s):  
Nathan Davis ◽  
Tsungcheng Tsia ◽  
Benjamin Bass ◽  
Gemma Tedo ◽  
Sofia Morais ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Feed Intake ◽  
Random Effect ◽  
Body Weight Change ◽  
Lactation Performance ◽  
Thickness Change ◽  
Breaking Effect ◽  
Ad Libitum ◽  
Sow Lactation ◽  
The Impact

Abstract The addition of a sensory additive to sow diets during the summer improved feed intake during lactation, and litter performance. The aim of this study was to evaluate the impact of the sensory additive on sow lactation performance during cooler temperatures. Three consecutive groups (n = 61 total) of sows were farrowed during winter (October, December and January). Sows were weighed, and back fat depth was measured, at 110 d of gestation prior to entering the lactation room, and again at weaning. The sows were sorted by parity, and then allotted by BW at d 110 to Control or 0.075% sensory additive (Luctamax® SowVive, Lucta S.A., Spain). Experimental diets were offered upon entry to the lactation room and fed through weaning. Feed disappearance was recorded every three days. Sows were fed 2.72 kg/head/day until farrowing, and then allowed to eat ad libitum from 24 hours post-farrowing until weaning. Data were analyzed using the PROC MIXED procedure of SAS as an RCBD with treatment as the fixed effect and group as a random effect. No differences were observed on sows feed intake (P &gt; 0.4), 10th rib backfat thickness change (P = 0.632) and body weight change from d 110 of gestation to weaning (P = 0.65, Table 1). Sows fed the sensory additive lowered preweaning mortality by 4.9% (P = 0.051), and weaned an additional 1.42 piglets (P = 0.026) with similar weaning weights (P = 0.86) when compared to control. In conclusion, in the current study, lactation diets supplemented with a sensory additive improved litter performance and helped maintain sow body condition.

Caecotrophes intake in growing rabbits estimated either from urinary excretion of purine derivatives or from direct measurement using animals provided with a neck collar: effect of type and level of dietary carbohydrate

2002 ◽  
Vol 74 (1) ◽  
pp. 135-144 ◽  
Author(s):  
A. Belenguer ◽  
J. Balcells ◽  
M. Fondevila ◽  
C. Torre
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Purine Derivatives ◽  
Lower Growth ◽  
Beet Pulp ◽  
Lower Growth Rate ◽  
Maize Grain ◽  
G Ratio ◽  
Microbial N

AbstractThe present study compares estimates of caecotrophes production from urinary purine derivatives (PD) excretion with that from preventing caecotrophy by using a neck collar. A total of 64 New Zealand growing male rabbits were used to study the effect of diet composition on caecotrophes production. Diets were formulated using two sources of structural carbohydrates (fibre): alfalfa hay (AH) and sugar-beet pulp (SBP), mixed at two constant proportions, (0·75: 0·25) AH diets and (0·25: 0·75) SBP diets. Both diets included either barley or maize grain at two fibre: grain ratios (F/G, 80: 20 and 45: 55). Diets were given ad libitum. Growth rate, dry matter intake and digestibility were not modified by the grain source, although high F/G diets resulted in a lower growth rate (19·8 v. 26·4 g/day; P < 0·001). Between fibre sources, dry-matter intake and growth were higher in AH than in SBP diets (122·5 and 25·6 v. 101·6 and 20·4 g/day, respectively, P < 0·001 and P < 0·01). Rabbits given high F/G ratio and AH diets excreted more caecotrophes than those given low F/G ratio and SBP diets (19·5 and 20·9 v. 16·3 and 14·85 g/day, respectively). Microbial-N recycling through the caecotrophy process was higher when considering data from PD excretion (1·33 g/d) than when estimated by preventing caecotrophy (0·72 g/day).

Shape evolution of a spherical particle growing in supersaturated solution affected by straining flows

2016 ◽  
Vol 30 (06) ◽  
pp. 1650059
Author(s):  
Jingjing Gao ◽  
Mingwen Chen ◽  
Zidong Wang
Keyword(s):  
Growth Rate ◽  
Expansion Method ◽  
Supersaturated Solution ◽  
Shape Evolution ◽  
Interface Microstructure ◽  
Lower Growth ◽  
Ambient Flow ◽  
Multiple Variable ◽  
Lower Growth Rate ◽  
Asymptotic Expansion Method

The convection of ambient flow field has a significant influence on the pattern formation of growing particles. In this paper, we investigate the shape evolution of particles growing in supersaturated solution affected by straining flows. By using the multiple variable asymptotic expansion method, we obtain the asymptotic solution. The solution indicates that the interface microstructure is greatly affected by the straining flows. The flow results in a higher growth rate in the surface where it is incoming and a lower growth rate where it is outgoing. Besides, the flow also has effects on the concentration distribution.

Genetic components of growth and ultrasonic fat depth traits in Meishan and Large White pigs and their reciprocal crosses

1992 ◽  
Vol 54 (1) ◽  
pp. 105-115 ◽  
Author(s):  
C. S. Haley ◽  
E. d'Agaro ◽  
M. Ellis
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Subcutaneous Fat ◽  
Additive Effect ◽  
Food Conversion ◽  
Large White ◽  
Male And Female ◽  
Ad Libitum ◽  
The Impact

AbstractGenes from the Chinese Meishan pig have the potential to enhance reproductive performance of European pigs. In order to allow prediction of the impact of Meishan genes in a range of alternative improvement programmes all traits of economic importance must be evaluated and genetic crossbreeding effects estimated. Entire male and female pigs of four genotypes, purebred Meishan (MS) and Large White (LW) pigs and both reciprocal Fl crossbred genotypes (MS ♂ × LW ♀ and LW ♂ × MS ♀), were farrowed in Edinburgh and subsequently performance tested at either Edinburgh or Newcastle. In Edinburgh, animals were penned in groups of four and fed ad libitum between pen mean weights of approximately 30 and 80 kg. At the end of test fat depths at the shoulder, last rib and loin were measured ultrasonically. In Newcastle, animals were penned in groups of six and fed ad libitum between pen mean weights of approximately 30 and 70 kg. Genotypic means and genetic crossbreeding effects (additive and heterosis direct effects and additive maternal effects) were estimated using restricted maximum likelihood.When compared with the LW, the direct additive effect of genes from the MS produced increased growth rate up to the time of weaning, no change in growth rate between weaning and start of test and greatly reduced growth rate during the performance test. The maternal additive effect of genes from the MS was to reduce growth rate up to the time of weaning, with little effect thereafter. There was substantial direct heterosis for growth rate in all periods measured, but heterosis was less in males than in females during the performance test. The combined effect was such that, within sex, the LW and the two crossbred genotypes were of similar ages when they reached 70 and 80 kg, but MS pigs were 38 to 60 days older. The direct additive effect of MS genes was to increase subcutaneous fat levels and there was little evidence for the effects of maternal genes or direct heterosis on these traits. There was a direct additive effect of MS genes reducing food intake and increasing food conversion ratio and there was direct heterosis for increased food intake. There were significant interactions between genotype and sex. Male and female LW pigs had a similar performance but male MS pigs had slower growth rates on the performance test with lower food intakes, food conversion ratios and subcutaneous fat levels than the females.

Competition, Growth Rate, and CO2Fixation in Triazine-Susceptible and -Resistant Smooth Pigweed (Amaranthus hybridus)

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 438-444 ◽  
Author(s):  
William H. Ahrens ◽  
E. W. Stoller
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Lower Growth ◽  
Amaranthus Hybridus ◽  
Relative Growth ◽  
Lower Growth Rate ◽  
Net Assimilation ◽  
Synthetic Capacity ◽  
Smooth Pigweed

Triazine-susceptible (S) and -resistant (R) biotypes of smooth pigweed (Amaranthus hybridusL.) were grown in the field under competitive conditions at varying initial proportions of S and R plants. R plants were less competitive than S plants as measured by accumulation of total above-ground dry weight and seed dry weight. S and R plants were also grown in the field under non-competitive conditions at 100, 40, and 10% light. Growth rate at 10% light did not differ between S and R plants. At the two higher light intensities, dry-matter accumulation 11 weeks after seeding was about 40% less in the R plants. At 100% light, relative growth rate and net assimilation rate were lower in the R plants by about 3.5 and 19%, respectively. The light- and CO2-saturated rates of CO2fixation in intact leaves of glasshouse-grown R plants were 20% less than those in S plants. An apparent 10 and 20% greater number of chlorophyll molecules per photosystem II reaction center in R plants (as compared with S plants) grown in the field at 40 and 100% light, respectively, did not explain differences between the S and R biotypes in photo synthetic capacity. The S and R plants did not differ in specific leaf weight or chlorophyll content on a leaf-area basis. Lower growth rate of R plants may be responsible for inferior competitive ability of R biotypes and could be the result of an impaired photosynthetic capacity.

scholarly journals Physiological Characterization of an Anaerobic Ammonium-Oxidizing Bacterium Belonging to the “Candidatus Scalindua” Group

2013 ◽  
Vol 79 (13) ◽  
pp. 4145-4148 ◽  
Author(s):  
Takanori Awata ◽  
Mamoru Oshiki ◽  
Tomonori Kindaichi ◽  
Noriatsu Ozaki ◽  
Akiyoshi Ohashi ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Ammonium Oxidation ◽  
Lower Growth ◽  
Content Type ◽  
Physiological Characterization ◽  
Phylogenetic Affiliation ◽  
Lower Growth Rate

ABSTRACTThe phylogenetic affiliation and physiological characteristics (e.g.,Ksand maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “CandidatusScalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “CandidatusScalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species.

Effect of feed restriction and subsequent re-alimentation on hormones and genes of the somatotropic axis in cattle

2015 ◽  
Vol 47 (7) ◽  
pp. 264-273 ◽  
Author(s):  
Kate Keogh ◽  
Sinéad M. Waters ◽  
Alan K. Kelly ◽  
Alastair R. G. Wylie ◽  
David A. Kenny
Keyword(s):  
Growth Hormone ◽  
Compensatory Growth ◽  
Hepatic Tissue ◽  
Feed Restriction ◽  
Lower Growth ◽  
Somatotropic Axis ◽  
Hepatic Expression ◽  
Period 2 ◽  
Lower Growth Rate ◽  
Ad Libitum

The objective of this study was to characterize the effect of feed restriction and compensatory growth during re-alimentation on the functionality of the somatotropic axis. We blocked 60 bulls into one of two groups: 1) restricted feed allowance for 125 days ( period 1) (RES, n = 30) followed by ad libitum feeding for 55 days ( period 2) or 2) ad libitum access to feed throughout (ADLIB, n = 30). A growth hormone releasing hormone (GHRH) challenge was performed during each period. At the end of each period, 15 animals from each treatment were slaughtered and hepatic tissue collected. Hepatic expression of 13 genes of the somatotropic axis was measured by qRT-PCR. RES displayed a lower growth rate during period 1 (0.6 vs. 1.9 kg/day; P < 0.001), subsequently gaining more than ADLIB animals during period 2 (2.5 vs. 1.4 kg/day; P < 0.001). Growth hormone response to GHRH was not different between treatments at either time-point ( P > 0.05); however, resultant plasma IGF-1 was lower in period 1 and greater in period 2 in RES animals ( P < 0.05). Expression of IGFBP2 was higher ( P < 0.01) and IGF1 ( P < 0.001) and GHRIA ( P < 0.05) lower in RES compared with ADLIB during period 1, with no difference evident in period 2 ( P > 0.05). Collectively, the results of this study are consistent with uncoupling of the somatotropic axis following feed restriction. However, there is no evidence from this study that the somatotropic axis per se is a significant contributor to compensatory growth.

RESPONSE OF GROWING-FINISHING PIGS TO DIETARY INCLUSION OF GREEN FOXTAIL (Setaria viridis) SEEDS

1984 ◽  
Vol 64 (4) ◽  
pp. 1063-1066
Author(s):  
A. G. CASTELL
Keyword(s):  
Growth Rate ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Growing Pigs ◽  
Carcass Composition ◽  
Apparent Digestibility ◽  
Finishing Pigs ◽  
Setaria Viridis ◽  
Green Foxtail ◽  
Ad Libitum

Increasing the level of wheat screenings (95% green foxtail seeds) from 0 to 25% in diets fed ad libitum over the period from 34 to 89 kg liveweight resulted in an increased daily feed intake (P < 0.05), reduced (P < 0.05) feed efficiency and apparent digestibility, but produced no consistent effects on growth rate or carcass composition. Key words: Growing pigs, green foxtail, Setaria viridis, carcass, digestibility

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